Osmunda regalis

Osmunda regalis is unusual in that it forms new fertile
fronds in autumn, and not in spring or summer as is common in most
ferns.

Description
Plants form huge, light green rosettes of up to 1.5 m high under
favourable conditions. Young fronds (leaves) are covered in a hairy
felt as they emerge, but become hairless at maturity.
The bipinnate (doubly divided) fronds are lanceolate (lance-shaped
and tapering towards the tip), rather leathery and can be as large
as 600-1 200 x 300-450 mm. The elongated, blunt-tipped pinnules
(leaflets) have serrated edges and turn from red to green as they
mature.

The fertile pinnules at the tip of each fertile frond are narrowed,
clustered and apparently totally covered with sporangia (spore-bearing
structures). These
sporangia, which are green when young, but darken to brown at maturity,
are large and not in sori (clusters of sporangia).

The erect, fertile fronds in the centre of the plant project above
the outer spreading, sterile fronds.

Plants have a massive creeping rhizome (root system) and the rootstock
can protrude several centimetres above the ground like a short trunk
covered with leaf sheaths and roots.

DistributionOsmunda regalis is an almost cosmopolitan species. It occurs
in Europe, North, Central and South America, Asia, Africa, Madagascar
and the Mascarene Islands, but is not found in Australia or New
Zealand. In southern Africa it is commonly found in the wetter regions
and prefers areas with an annual rainfall of 400-1 200 mm per annum.
It has a wide altitudinal range in southern Africa, occurring from
near sea level to 2 000 m. The species is abundant in the warmer,
low-altitude regions along the base of the Eastern Escarpment and
becomes less frequent at higher altitudes. It often occurs in woodland
and forest, but generally requires fairly high light intensity.
It can form large colonies and always grows near water, along rivers
and streambanks, where the rhizome is continually bathed in running
water. It is less common in wet grasslands, in half to full shade,
and is rarely found in open positions, on sand or gravel soils.

Derivation of name and historical aspects
The origin of this fern's name is too old to be traced. Possible
derivations include the Saxon name 'Osmond' for the Germanic god
Thor, or combining the Latin os (= mouth) and mundus
(= clean), as it was reputedly used to clean the mouth. Another
possibility is that it was named after King Osmund, who reigned
over the South Saxons about 758 A.D. If this is true, the specific
epithet regalis, meaning royal, would then be obvious. It
may also refer to the fact that this species is very widespread
in Europe, or to the stately growth of the plant.

The family Osmundaceae is an isolated and primitive group with
no close relations. Osmundaceae fossils are known from as far back
as the Permian (290-248 million years ago), while modern Osmunda
fossils have been found in Upper Cretaceous sediments (up to 65
million years ago). The genus Osmunda comprises approximately
seven species, of which only O. regalis, also the largest
member of the genus, occurs in southern Africa. The only other representative
of the family in southern Africa is Todea barbara.

Uses and cultural aspects
The rhizome of this plant was used as a remedy in Europe against
rickets and abscesses. Patients also had to sleep on a bed made
of the herbaceous parts of the plant. Poultices or emollients containing
Osmunda regalis rootstock are reputedly an effective treatment
for bruises, burns, sprains, broken bones and ulcers. The stem was
used as an astringent and a tonic. When the root is slowly simmered
in water it breaks down to a mucilaginous mass that was very popular
for stiffening linen. The fibrous roots do not compact or soften
easily and have long been used as a growing medium in the cultivation
of orchids and other plants.

Its large size, longevity and the distinctly different sterile
and fertile parts make this slow-spreading species an ideal accent
plant for landscaping. It is especially useful for waterside planting,
but needs space to be fully appreciated. It grows well in shade,
but tolerates full sun if it receives plenty of moisture and will
thrive in wet, boggy soils. These ideal conditions should be matched
as closely as possible when cultivating this species in the garden.
Osmunda regalis requires a cold winter, and this is maybe
the reason why, in southern Africa, this species tends not to form
the massive plants (with fronds of up to 3.3 m in favourable conditions)
seen in Europe. It also restricts the use of this fern as a houseplant.

The royal fern can be propagated by dividing the crown before the
new spring growth uncoils and planting the divisions in well-prepared
soil. Division must only be done when absolutely necessary and the
wounds must be sealed to prevent fungus infection. This species
prefers acid to neutral soil, rich in humus. A mixture of loam,
sharp sand and leaf mould or peat can be added to the soil when
preparing for planting. It can also be easily grown from spores.
Bear in mind that Osmunda has green spores and these must
be sown fresh. Viable spores germinate quickly, often within a day.